Functional imaging of complex movement: insights into the pathophysiology of apraxia

Apraxia is a disorder of motor cognition affecting different aspects of complex voluntary movement. The most common form of apraxia, ideo-motor apraxia (IMA), is clinically assessed by tests of movement imitation. Some patients with IMA show a dissociation between the imitation of abstract and symbolic movements. The second important form of apraxia, ideational apraxia (IA), is characterized by deficient object use. Finally, apraxic patients generally exhibit deficits in the spatial and temporal organisation of (goal-directed) movement sequences. Motivated by these diverse clinical observations of deficient volu…